poi-ooxml/src/test/java/org/apache/poi/xssf/XSSFTestDataSamples.java

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   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
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       http://www.apache.org/licenses/LICENSE-2.0

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   distributed under the License is distributed on an "AS IS" BASIS,
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   See the License for the specific language governing permissions and
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package org.apache.poi.xssf;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import org.apache.poi.hssf.HSSFTestDataSamples;
import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.util.TempFile;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

/**
 * Centralises logic for finding/opening sample files in the test-data/spreadsheet folder.
 *
 * @author Josh Micich
 */
public class XSSFTestDataSamples {
    /**
     * Used by {@link #writeOutAndReadBack(Workbook, String)}.  If a
     * value is set for this in the System Properties, the xlsx file
     * will be written out to that directory.
     */
    public static final String TEST_OUTPUT_DIR = "poi.test.xssf.output.dir";

    public static File getSampleFile(String sampleFileName) {
        return HSSFTestDataSamples.getSampleFile(sampleFileName);
    }
    public static OPCPackage openSamplePackage(String sampleName) {
        try {
            return OPCPackage.open(HSSFTestDataSamples.openSampleFileStream(sampleName));
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
    public static XSSFWorkbook openSampleWorkbook(String sampleName) {
        InputStream is = HSSFTestDataSamples.openSampleFileStream(sampleName);
        try {
            return new XSSFWorkbook(is);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * Write out workbook <code>wb</code> to {@link #TEST_OUTPUT_DIR}/testName.xlsx
     * (or create a temporary file if <code>TEST_OUTPUT_DIR</code> is not defined).
     *
     * @param wb the workbook to write
     * @param testName a fragment of the filename
     * @return the location where the workbook was saved
     * @throws IOException If writing the file fails
     */
    public static <R extends Workbook> File writeOut(R wb, String testName) throws IOException {
        final File file = getOutputFile(testName);
        writeOut(wb, file);
        return file;
    }

    private static <R extends Workbook> void writeOut(R wb, File file) throws IOException {
        try (FileOutputStream out = new FileOutputStream(file)) {
            wb.write(out);
        }
    }

    // Anticipates the location of where a workbook will be written to
    // Note that if TEST_OUTPUT_DIR is not set, this will create temporary files
    // with unique names. Subsequent calls with the same argument may return a different file.
    // Gets a test data sample file, deleting the file if it exists.
    // This is used in preparation for writing a workbook out to the returned output file.
    // testName is a filename fragment and should not include the extension
    private static File getOutputFile(String testName) throws IOException {
        final String testOutputDir = System.getProperty(TEST_OUTPUT_DIR);
        final File file;
        if (testOutputDir != null) {
            // In case user provided testName with a file extension, don't repeat the file extension a second time
            final String testNameWithExtension = testName.endsWith(".xlsx") ? testName : testName + ".xlsx";
            // FIXME: may want to defer to the TempFile with a persistent file creation strategy to the test output dir
            // This would add the random value in the middle of the filename so that test runs wouldn't overwrite files
            file = new File(testOutputDir, testNameWithExtension);
        }
        else {
            file = TempFile.createTempFile(testName, ".xlsx");
        }
        if (file.exists()) {
            if(!file.delete()) {
                throw new IOException("Could not delete file " + file);
            }
        }
        return file;
    }

    /**
     * Write out workbook <code>wb</code> to a memory buffer
     *
     * @param wb the workbook to write
     * @return the memory buffer
     * @throws IOException If writing the file fails
     */
    public static <R extends Workbook> ByteArrayOutputStream writeOut(R wb) throws IOException {
        ByteArrayOutputStream out = new ByteArrayOutputStream(8192);
        wb.write(out);
        return out;
    }

    /**
     * Write out the workbook then closes the workbook.
     * This should be used when there is insufficient memory to have
     * both workbooks open.
     *
     * Make sure there are no references to any objects in the workbook
     * so that garbage collection may free the workbook.
     *
     * After calling this method, null the reference to <code>wb</code>,
     * then call {@link #readBack(File)} or {@link #readBackAndDelete(File)} to re-read the file.
     *
     * Alternatively, use {@link #writeOutAndClose(Workbook)} to use a ByteArrayOutputStream/ByteArrayInputStream
     * to avoid creating a temporary file. However, this may complicate the calling
     * code to avoid having the workbook, BAOS, and BAIS open at the same time.
     *
     * @param wb The workbook to write out, it is closed after the call.
     * @param testName file name to be used to write to a file. This file will be cleaned up by a call to readBack(String)
     * @return workbook location
     * @throws RuntimeException if {@link #TEST_OUTPUT_DIR} System property is not set
     */
    public static <R extends Workbook> File writeOutAndClose(R wb, String testName) {
        try {
            File file = writeOut(wb, testName);
            // Do not close the workbook if there was a problem writing the workbook
            wb.close();
            return file;
        }
        catch (final IOException e) {
            throw new RuntimeException(e);
        }
    }


    /**
     * Write out workbook <code>wb</code> to a memory buffer,
     * then close the workbook
     *
     * @param wb the workbook to write
     * @return the memory buffer
     * @throws RuntimeException If writing the file fails
     */
    public static <R extends Workbook> ByteArrayOutputStream writeOutAndClose(R wb) throws IOException {
        ByteArrayOutputStream out = writeOut(wb);
        // Do not close the workbook if there was a problem writing the workbook
        wb.close();
        return out;
    }

    /**
     * Read back a workbook that was written out to a file with
     * {@link #writeOut(Workbook, String))} or {@link #writeOutAndClose(Workbook, String)}.
     * Deletes the file after reading back the file.
     * Does not delete the file if an exception is raised.
     *
     * @param file the workbook file to read and delete
     * @return the read back workbook
     * @throws IOException If reading or deleting the file fails
     */
    public static XSSFWorkbook readBackAndDelete(File file) throws IOException {
        XSSFWorkbook wb = readBack(file);
        // do not delete the file if there's an error--might be helpful for debugging
        if(!file.delete()) {
            throw new IOException("Could not delete file " + file + " after reading");
        }
        return wb;
    }

    /**
     * Read back a workbook that was written out to a file with
     * {@link #writeOut(Workbook, String)} or {@link #writeOutAndClose(Workbook, String)}.
     *
     * @param file the workbook file to read
     * @return the read back workbook
     * @throws IOException If reading the file fails
     */
    public static XSSFWorkbook readBack(File file) throws IOException {
        try (InputStream in = new FileInputStream(file)) {
            return new XSSFWorkbook(in);
        }
    }

    /**
     * Read back a workbook that was written out to a memory buffer with
     * {@link #writeOut(Workbook)} or {@link #writeOutAndClose(Workbook)}.
     *
     * @param out the output stream to read back from
     * @return the read back workbook
     * @throws IOException If reading the file fails
     */
    public static XSSFWorkbook readBack(ByteArrayOutputStream out) throws IOException {
        try (InputStream is = new ByteArrayInputStream(out.toByteArray())) {
            out.close();
            return new XSSFWorkbook(is);
        }
    }

    /**
     * Write out and read back using a memory buffer to avoid disk I/O.
     * If there is not enough memory to have two workbooks open at the same time,
     * consider using:
     *
     * Workbook wb = new XSSFWorkbook();
     * String testName = "example";
     *
     * <code>
     * File file = writeOutAndClose(wb, testName);
     * // clear all references that would prevent the workbook from getting garbage collected
     * wb = null;
     * Workbook wbBack = readBackAndDelete(file);
     * </code>
     *
     * @param wb the workbook to write out
     * @return the read back workbook
     */
    public static <R extends Workbook> R writeOutAndReadBack(R wb) {
        Workbook result;
        try {
            result = readBack(writeOut(wb));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        @SuppressWarnings("unchecked")
        R r = (R) result;
        return r;
    }

    /**
     * Write out, close, and read back the workbook using a memory buffer to avoid disk I/O.
     *
     * @param wb the workbook to write out and close
     * @return the read back workbook
     */
    public static <R extends Workbook> R writeOutCloseAndReadBack(R wb) {
        Workbook result;
        try {
            result = readBack(writeOutAndClose(wb));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        @SuppressWarnings("unchecked")
        R r = (R) result;
        return r;

    }

    /**
     * Writes the Workbook either into a file or into a byte array, depending on presence of
     * the system property {@value #TEST_OUTPUT_DIR}, and reads it in a new instance of the Workbook back.
     * If TEST_OUTPUT_DIR is set, the file will NOT be deleted at the end of this function.
     * @param wb workbook to write
     * @param testName file name to be used if writing into a file. The old file with the same name will be overridden.
     * @return new instance read from the stream written by the wb parameter.
     */

    public static <R extends Workbook> R writeOutAndReadBack(R wb, String testName) {
        if (System.getProperty(TEST_OUTPUT_DIR) == null) {
            return writeOutAndReadBack(wb);
        } else {
            try {
                Workbook result = readBack(writeOut(wb, testName));
                @SuppressWarnings("unchecked")
                R r = (R) result;
                return r;
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
    }
}